'''同切圆的绘制。绘制一组半径不同的同切圆，如图1.18所示。
turtle.pensize(3)
turtle.circle(20)    #绘制直径为20像素的圆
turtle.circle(40)
turtle.circle(80)
turtle.circle(160)
'''
import turtle
turtle.pensize(3)
turtle.circle(20)    #绘制直径为20像素的圆
turtle.circle(40)
turtle.circle(80)
turtle.circle(160)

